Implement end() method in DeltaBundler

Reviewed By: jeanlauliac

Differential Revision: D5803466

fbshipit-source-id: 78a29cd943774506694513987d97d9f37be04485

packages/metro-bundler/src/DeltaBundler/__tests__/DeltaBundler-test.js

@@ -0,0 +1,106 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails oncall+javascript_foundation
+ * @format
+ */
+
+'use strict';
+
+jest.mock('../DeltaTransformer');
+jest.mock('../../Bundler');
+
+const Bundler = require('../../Bundler');
+const DeltaTransformer = require('../DeltaTransformer');
+
+const DeltaBundler = require('../');
+
+describe('DeltaBundler', () => {
+  let deltaBundler;
+  let bundler;
+  const initialTransformerResponse = {
+    pre: new Map([[1, {code: 'pre'}]]),
+    post: new Map([[2, {code: 'post'}]]),
+    delta: new Map([[3, {code: 'module3'}], [4, {code: 'another'}]]),
+    inverseDependencies: [],
+    reset: true,
+  };
+
+  beforeEach(() => {
+    DeltaTransformer.prototype.getDelta = jest
+      .fn()
+      .mockReturnValueOnce(Promise.resolve(initialTransformerResponse));
+
+    DeltaTransformer.create = jest
+      .fn()
+      .mockReturnValue(Promise.resolve(new DeltaTransformer()));
+
+    bundler = new Bundler();
+    deltaBundler = new DeltaBundler(bundler, {});
+  });
+
+  it('should create a new transformer to build the initial bundle', async () => {
+    expect(await deltaBundler.build({deltaBundleId: 10})).toEqual({
+      ...initialTransformerResponse,
+      id: 10,
+    });
+
+    expect(DeltaTransformer.create.mock.calls.length).toBe(1);
+  });
+
+  it('should reuse the same transformer after a second call', async () => {
+    const secondResponse = {
+      delta: new Map([[3, {code: 'a different module'}]]),
+      pre: new Map(),
+      post: new Map(),
+      inverseDependencies: [],
+    };
+
+    DeltaTransformer.prototype.getDelta.mockReturnValueOnce(
+      Promise.resolve(secondResponse),
+    );
+
+    await deltaBundler.build({deltaBundleId: 10});
+
+    expect(await deltaBundler.build({deltaBundleId: 10})).toEqual({
+      ...secondResponse,
+      id: 10,
+    });
+
+    expect(DeltaTransformer.create.mock.calls.length).toBe(1);
+  });
+
+  it('should reset everything after calling end()', async () => {
+    await deltaBundler.build({deltaBundleId: 10});
+
+    deltaBundler.end();
+
+    await deltaBundler.build({deltaBundleId: 10});
+
+    expect(DeltaTransformer.create.mock.calls.length).toBe(2);
+  });
+
+  it('should build the whole stringified bundle', async () => {
+    expect(
+      await deltaBundler.buildFullBundle({deltaBundleId: 10}),
+    ).toMatchSnapshot();
+
+    DeltaTransformer.prototype.getDelta.mockReturnValueOnce(
+      Promise.resolve({
+        delta: new Map([[3, {code: 'modified module'}], [4, null]]),
+        pre: new Map([[5, {code: 'more pre'}]]),
+        post: new Map([[6, {code: 'bananas'}], [7, {code: 'apples'}]]),
+        inverseDependencies: [],
+      }),
+    );
+
+    expect(
+      await deltaBundler.buildFullBundle({deltaBundleId: 10}),
+    ).toMatchSnapshot();
+  });
+});

packages/metro-bundler/src/DeltaBundler/__tests__/__snapshots__/DeltaBundler-test.js.snap

@@ -0,0 +1,23 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`DeltaBundler should build the whole stringified bundle 1`] = `
+Object {
+  "bundle": "pre
+;module3
+;another
+;post",
+  "numModifiedFiles": 4,
+}
+`;
+
+exports[`DeltaBundler should build the whole stringified bundle 2`] = `
+Object {
+  "bundle": "pre
+;more pre
+;modified module
+;post
+;bananas
+;apples",
+  "numModifiedFiles": 5,
+}
+`;

packages/metro-bundler/src/DeltaBundler/index.js

@@ -60,6 +60,12 @@ class DeltaBundler {
     this._options = options;
   }
 
+  end() {
+    this._deltaTransformers.forEach(DeltaTransformer => DeltaTransformer.end());
+    this._deltaTransformers = new Map();
+    this._deltaPatchers = new Map();
+  }
+
   async build(options: Options): Promise<DeltaBundle> {
     const {deltaTransformer, id} = await this.getDeltaTransformer({
       ...options,

packages/metro-bundler/src/Server/index.js

@@ -297,8 +297,9 @@ class Server {
     });
   }
 
-  end(): mixed {
-    return this._bundler.end();
+  end() {
+    this._deltaBundler.end();
+    this._bundler.end();
   }
 
   setHMRFileChangeListener(